ceph: fix inode removal from snap realm when racing with migration
When an inode was dropped while being migrated between two MDSs,
i_cap_exporting_issued was non-zero such that issue caps were non-zero and
__ceph_is_any_caps(ci) was true. This prevented the inode from being
removed from the snap realm, even as it was dropped from the cache.
Fix this by dropping any residual i_snap_realm ref in destroy_inode.
Signed-off-by: Sage Weil <sage@newdream.net>
diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c
index 7abe1ae..aca82d5 100644
--- a/fs/ceph/inode.c
+++ b/fs/ceph/inode.c
@@ -378,6 +378,22 @@
ceph_queue_caps_release(inode);
+ /*
+ * we may still have a snap_realm reference if there are stray
+ * caps in i_cap_exporting_issued or i_snap_caps.
+ */
+ if (ci->i_snap_realm) {
+ struct ceph_mds_client *mdsc =
+ &ceph_client(ci->vfs_inode.i_sb)->mdsc;
+ struct ceph_snap_realm *realm = ci->i_snap_realm;
+
+ dout(" dropping residual ref to snap realm %p\n", realm);
+ spin_lock(&realm->inodes_with_caps_lock);
+ list_del_init(&ci->i_snap_realm_item);
+ spin_unlock(&realm->inodes_with_caps_lock);
+ ceph_put_snap_realm(mdsc, realm);
+ }
+
kfree(ci->i_symlink);
while ((n = rb_first(&ci->i_fragtree)) != NULL) {
frag = rb_entry(n, struct ceph_inode_frag, node);